Roof Area Calculator
True roof area from footprint area and pitch angle.
Amortization schedule
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Showing first 12 of months.
Growth over time
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Introduction
Roof Area Calculator — True roof area from footprint area and pitch angle. Enter Footprint area (m²), Pitch angle (°) to get an instant, accurate result.
Formula
Roof (sloped) area = footprint area ÷ cos(pitch angle), the standard formula for converting a flat footprint into actual sloped roof surface area.
Step-by-step
- Enter the Footprint area (m²).
- Enter the Pitch angle (°).
- Click Calculate to see your result instantly.
Real-world example
Example: With Footprint area (m²) = 100, Pitch angle (°) = 30, the Roof Area Calculator gives Roof Area M2: 115.4701.
Frequently Asked Questions
Why divide by cosine of the pitch angle?
A sloped roof surface is longer than its flat footprint by a factor of 1/cos(angle) — steeper roofs (larger angles) have proportionally more surface area.
How do I find my pitch angle if I only know rise/run?
Use the Roof Pitch calculator first to convert rise and run into degrees, then use that angle here.
What inputs does the Roof Area Calculator need?
You'll need to provide: Footprint area (m²), Pitch angle (°). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Roof Area Calculator?
The Roof Area Calculator applies the formula exactly as calculated — Roof (sloped) area = footprint area ÷ cos(pitch angle), the standard formula for converting a flat footprint into actual sloped roof surface area. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Roof Area Calculator free to use?
Yes, the Roof Area Calculator is completely free, requires no signup, and runs instantly in your browser.
About the Roof Area Calculator
The Roof Area Calculator uses a real, verifiable formula — Roof (sloped) area = footprint area ÷ cos(pitch angle), the standard formula for converting a flat footprint into actual sloped roof surface area. — so results are accurate every time, not an approximation.